Kenwood Stereo in 5KCS problem

[Steve Sherman]

I've been playing around with the wiring for my 87 5KTQW and this
Kenwood stereo system.  The wagon had up til now used the stock
radio/cassette and has the stock Bose system in it.  I think I have
things figured out, except for one annoying and killer problem.  I was
hoping someone who might have figured this out...

Power/ground/ front speakers all pretty normal.  For the rear speakers,
I was trying to follow a post in the archives.  I connected the rear amp
power to the power antenna lead of the new stereo, and connected just
one of the speaker leads to the new stereo for each rear channel.  Odd
thing is, if the stereo is playing when I connect the rear speaker
leads, everything is fine.  However if the rear leads are connected when
the stereo is turned on, then no speaker output anywhere...

I suspect some odd check in the new stereo, that is checking to see
what's connected, or maybe the rear amp looks like a short as it is
being powered up?  Probably other possibilities too.

Anyhow, I was hoping someone on the list had run into this before and
come up with a solution, the magic resistor here or whatever.

TIA